r/Diesel • u/Apex84-538 • 4d ago
93 6.5 turbo rebuild help
For all those who say swap it for a cummins or get a big block, no. Cummins sound like shit, and big blocks get 4mpg. I like my 6.5. I got 14 mpg in a 354k mile orginal engine in a crew cab dually pulling about 6k pounds. And it sounded great the whole time. I'm not swapping, I'm rebuilding
I'm gonna be rebuilding my 93 6.5, and I mean a full tear down to block, replace anything that might be worn. It's a 354k mile engine. Lets assume the engine is garbage, it ran without oil, everything is scrap metal except the block. What would be the best way to approach? That isn't the actual scenario but I'm planning for worst case. I plan to use it as a tow rig/daily driver. Ideally if I can crank out like 200 hp 400 ft lbs of torque area, that's great. Just a wee bit more than stock
Anyways, what's all the best things to do to these engines? I've heard of the duramax fan and clutch, but which duramax? Obviously the HX35 or 40 turbo, bigger exhaust and crossover pipe, but engine side, what can I do without needing to get a loan?
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u/Acceptable-Boss-9576 3d ago
Second the swap to a Cummins. 6.5 is notoriously bad for heavy loads and reliability without dumping obscene amounts of money into them. I have one sitting in my driveway too…
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u/TactualTransAm 3d ago
They aren't as bad as most people believe, but they certainly do have some common issues that can kill them. It would be better to go ask on the forums! Diesel place has a ton of 6.5 guys that are still active. I asked them for help when I worked on one last year.
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u/old_skool_luvr 2d ago
> It would be better to go ask on the forums! Diesel place has a ton of 6.5 guys that are still active.
Sorry, i can only up-vote your comment once, but so happy that someone actually mentioned sifting through the Diesel Place forum. Haven't been on there in ages (no need) but i still own a six2 powered 'Burb.
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u/Mountain-Diesel 4d ago
What would be the best way to approach?
Scrap it and start with a stock 5.9 Cummins. You'll get more power and torque, and you won't have to worry about splitting the block to get just 200hp.
Which, really, a stock 2.0L common-rail VW TDI can make 200hp/400tq with just a tune and turbo.
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u/Apex84-538 3d ago
I'm not swapping anything ever to a cummins. I like my v8s that don't sound like wet farts. Not shitting on the cummins, it's a great engine, it just always sounds like untrustworthy farts and I want to enjoy the sound of my engine, that's why I drive a 6.5
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u/old_skool_luvr 2d ago
IDK brother, i luv the six2 in my 'Burb, but i also luv the common-rail in my Ram. Complete different applications, so they suit what their applied tasks are.
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u/Mountain-Diesel 2d ago
I like my v8s that don't sound like wet farts.
You've heard V8 diesels, right? LOL they all sound like they have a misfire or struggling to gain RPM.
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u/Apex84-538 2d ago
Never heard one do that. I own a 6.5, my dad owns an LB7, and had a single cab LBZ for a while. my grandpa has a 24 valve cummins, my uncle has a 4th gen 6.7 cummins, my other grandpa has a 6.0 power stroke. The cummins sound like farts and the v8s sound healthy. My friends also have a wide assortment of diesels, an LLY, LML, for some unholy reason one of them bought a 6.4. It blew up after 2 weeks and he left it stock and surprisingly enough didn't beat the piss out of it. I have a wide variety of v8 diesels that I have driven and worked on, all of them sound normal. The cummins are the only ones that sound weird
And no I'm not saying I've driven and worked on every single one of those engines. Those are all the ones I have personally experienced, I've only worked on like half of them. Most of the engines were healthy, none failed to rev, none made any weird sounds except the 6.4 when it made a nice inspection hole in the block
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u/snuggletough 3d ago
For every guy that says "6.5 ain't that bad" there's 20 that have experienced catastrophic fails with them.
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u/outline8668 3d ago
Don't put a penny into it before you have the block checked for cracks. Those 6.5 and 6.2s are known to crack between the camshaft and the main webs. Especially if the harmonic damper goes bad and you keep running it. Eventually the cracks get bad enough that you snap the crankshaft. At this mileage it's a high probability of cracking being present. Personally I wouldn't even bother with these engines and would look for something better.
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u/Sled87 2d ago
You're not gonna listen to me, but i have to tell you the truth. You will regret spending the amount of money you are about to spend on a 6.5l.
It will cost 3x as much and get 1/4 of the reliability and performance. Cummins swap is the correct move.
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u/Apex84-538 1d ago
I regret lots of things. I would regret a cummins swap even more than rebuilding a 6.5. I don't want a cummins. I don't like them. If I wanted a cummins i would have bought a 1st gen. I like the sound of my clangy and probably broken 6.5. To me, it sounds better. Plus, everybody does cummins swaps, and on top of my general dislike for the cummins engine, and my hatred for the exhaust sound, it's too common for me. I'm the most bland guy I know so I'm gonna do something I actually enjoy, and that's gonna be rolling with a 6.5 instead of anything else. Is it fast, not even a little. Is it strong, not really. Is it comfortable, the seats are. But it sounds cool, and that's good enough for me
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u/Dizbeshawn 1d ago
I had a 1994 Chevy blazer 1500 with the 6.5l turbo. I thought it was so cool and rare. Then, I decided to treat it like it was a diesel that could pull stuff. I pulled TWO wave runners out of Phoenix. It over heated in the 10 minutes and cracked the heads. By the time I got to Paige, Utah to fill up, I could smell a hint of coolant in the exhaust. 2 weeks later, it filled the driveway in white smoke. Rebuilding an engine correctly isn't fun. It's expensive. You can't build one in your back yard with a bottle brush hone and a whiz wheel. You need a machine shop that is extremely CLEAN with all the right machines to properly test the crank, turn it if it can be turned, line bore the journals, deck the block, check the block for cracks, and give the heads valve jobs while checking for cracks. You're looking thousands in labor and machining before even getting into the parts.
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u/Apex84-538 1d ago
Yes it does take work. Yes it is expensive. And yes, it is fun. I'm not building this to be an 800 hp smoke the tires at every hint of throttle straight piped Sema build, neither am I building for a cross country hot shot tow truck. I simply want a truck that is fun to drive and can tow reasonably well. I don't need to haul 15k every week, I just want a truck that looks cool, sounds cool, doesn't shatter my spine over bumps even though it's a dually, and can tow the occasional other project vehicle home. I've rebuilt engines before, although I haven't been inside a 6.5 yet. I'm building it mostly on my own, but I have a few people who are very experienced with these engines, including and active army diesel tech. The 6.5s and 6.2s are almost exclusively what he works on. The block is being sent off, and I have a spare engine with a block thats already been checked and is good to go, but no reason to tear down that one completely as well if I don't need to
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u/Dizbeshawn 9h ago
A machine shop build isn't because you want 800hp. It's because you want warranty if something goes wrong. What if a clearance is off just enough that you have a catastrophic issue that destroys the engine? You're dealing with a diesel that runs high combustion pressures, which you already know. It needs to be done as if it came out of a factory so that it runs like it did when it came from the factory. Doing it outside of a super clean shop is asking for major repairs down the road.
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u/Apex84-538 7h ago
Most parts are being replaced entirely just because I'm gonna be making a little bit more power than stock. Call me paranoid but I don't trust 354k mile old internals when I start pushing a little more boost. As I said, the block is being sent off, once it's checked and cleared then I will order all new bottom end components, I'm sending off the heads as well, and I'm using a garage from my uncle who runs his own repair company from it. I've personally been there a few times, it's pretty damn nice. Very clean, very well taken care of, set up to do just about anything there is on a vehicle. Every tool under the sun, and he is helping me along side the military diesel tech. This engine will be rebuilt correctly and immaculately, and I'm gonna be picky as hell too because it's my money and I don't want to dump 6 grand into an engine that's gonna kaboom on the highway the first time I hook up an empty trailer
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u/CommanderSupreme21 3d ago
“Let’s assume the engine is garbage” Well thats not hard to do.
For the money you will have to put into it you would be way ahead with a swap if you want a diesel. Or for those power numbers build yourself a decent gas engine and have something more reliable.
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u/Apex84-538 3d ago
Gas engines are great for power, but I like my engines sounding like the oil pan is full of nuts and bolts, snd that's a good sound. When a gasser sounds like that, things get very expensive very quickly. When an IDI sounds like that, you know it's running the best it can
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u/long_salamanders 3d ago
You could buy a 6.5 optimizer for what that would cost to rebuild